Contribution of the MHC class II antigens to the etiology of infantile spasm in Mexican Mestizos

Purpose: Infantile spasms (ISs) are age-dependant epileptic seizures, which may be flexor, extensor, lightning or nods, or mixed. The aim of this stud y was the analysis of genetic factors within the human leukocyte antigen (H LA) complex associated with ISs. Methods: Sixty-five patients diagnosed according to the established interna tional criteria were compared with 229 healthy individuals; all of them wer e Mexican Mestizos. Five families were also analyzed (seven affected and fi ve healthy sibs); HLA class I and class II antigens were typed using the st andard microlymphocytotoxicity methods. Results: The findings showed female gender preference (2:1). Two thirds wer e symptomatic, and prevalent seizures were of mixed type (67%). A strong as sociation with HLA DR17 was detected in the IS group (pc < 0.01: OR = 3.6: EF = 0.20). DR17 was also found increased in the symptomatic patients (p = 0.009; OR = 3.16) and in those with other types of seizures (p = 0.001; OR = 2.0). Conversely, HLA-DQ6 was significantly decreased (pc < 0.002. PF = 0 .37) in the total and in the symptomatic groups (p < 0.01). Haplotype linka ge was not confirmed in the families; however, those with more than one aff ected sib shared at least one haplotype. Conclusions: These findings suggest the contribution of DR locus to the sus ceptibility and the participation of DQ region in the resistance to IS. Sev erity seems also to be influenced by HLA-DR17, and therefore class II typin g may be a helpful tool for disease prognosis.